Cardiff made the allegations to the FA two weeks ago and were asked to provide evidence, which they have now done.

However, the FA has previously declined to act over what it considers to be private correspondence. Premier League chief executive Richard Scudamore escaped censure earlier this year following newspaper revelations he had exchanged offensive emails with colleagues.

FA chairman Greg Dyke said at the time: "The FA does not as a matter of policy consider private communications sent with a legitimate expectation of privacy to amount to professional misconduct."